<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Gdata
 * @subpackage Gdata
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: MimeBodyString.php 16971 2009-07-22 18:05:45Z mikaelkael $
 */

/**
 * A wrapper for strings for buffered reading.
 *
 * @category   Zend
 * @package    Zend_Gdata_MimeBodyString
 * @subpackage Gdata
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Gdata_MimeBodyString
{

	/**
	 * The source string.
	 *
	 * @var string
	 */
	protected $_sourceString = '';

	/**
	 * The size of the MIME message.
	 * @var integer
	 */
	protected $_bytesRead = 0;

	/**
	 * Create a new MimeBodyString object.
	 *
	 * @param string $sourceString The string we are wrapping.
	 */
	public function __construct($sourceString)
	{
		$this->_sourceString = $sourceString;
		$this->_bytesRead = 0;
	}

	/**
	 * Read the next chunk of the string.
	 *
	 * @param integer $bytesRequested The size of the chunk that is to be read.
	 * @return string A corresponding piece of the string.
	 */
	public function read($bytesRequested)
	{
		$len = strlen($this->_sourceString);
		if($this->_bytesRead == $len) {
			return FALSE;
		} else if($bytesRequested > $len - $this->_bytesRead) {
			$bytesRequested = $len - $this->_bytesRead;
		}

		$buffer = substr($this->_sourceString, $this->_bytesRead, $bytesRequested);
		$this->_bytesRead += $bytesRequested;

		return $buffer;
	}

	/**
	 * The length of the string.
	 *
	 * @return int The length of the string contained in the object.
	 */
	public function getSize()
	{
		return strlen($this->_sourceString);
	}


}
